I've had the same problem as you multiple times.
If the turning off/on doesn't work, or the force restore, you'll likely have to restore from scratch again.
There are multiple threads on how to restart when this happens but it didn't work me...
I will say that the only thing that has worked for me, is to completely restore, and get rid of pretty much all my free apps/lite apps. I'm convinced (though of course without any actual proof) that it's because of one of these apps. Of course, which app, I have no idea...but ever since I've gotten rid of almost all my free apps, I don't have this problem anymore...